The life of the Church is the life of men in the Holy Trinity. In the Church all become one in Christ, all put on the deified humanity of the Son of God. “For as many as have been baptized into Christ have put on Christ” (Gal 3:27). The unity of the Church is the unity of many into one, the one Body of Christ, the one living temple of God, the one people and family of God.
Within the one body there are many individual members. Many “living stones” constitute the living temple. Many brothers and sisters make up the one family of which God is the Father. The unique diversity of each member of the one Body of Christ is guaranteed by the presence of the Holy Spirit. Each unique person is inspired by the Spirit to be a true man, a true son of God in his own distinct way. Thus, as the Body of the Church is one in Christ, the one Holy Spirit gives to each member the possibility of fulfilling himself in God and so of being one with all others in calling God “Father” (See 1 Cor 12).
The Church, then, as the perfect unity of many persons into one fully united organism, is a reflection of the Trinity itself. For the Church, being many unique and distinct persons, is called to be one mind, one heart, one soul and one body in the one Truth and Love of God Himself. The calling of the Church to be one in all things is the prototype of the vocation of all mankind which was originally created by God as many persons in one nature, ultimately destined by God for ever-more-perfect growth in free unity of Truth and Love, in the life of God’s Kingdom.